Abstract

Digital Homecages for Mice: A Novel 24/7 System for Multi-Week Monitoring of Mouse Behavior and Brain Electrophysiology

Ghimire A, Hale P, Kim D, Cerda I, Marino S, Ognjanovski N, Fitzgerald P, Vijayakumar P, Green A, Tang M, Chen Y, Akil H, Dinov I, Watson BO
ACNP 62nd Annual Meeting. 2023.

Abstract

Background: The neurobiology of phenomena underlying and contributing to stress response and depression are not fully understood. The development of further models and systems to study these in rodents can lead to mechanistic biological explanations that link to possibly translatable behavioral and physiological phenotypes.

Methods: Our strategy was to improve the resolution of behavioral monitoring in rodents over long time periods (weeks) in C57BL6 mice to both develop improved behavioral phenotypes and to link those to brain mechanism. We focus on both behavioral resolution and temporal resolution over weeks. Our system classifies sub-second resolution data into one of dozens of behaviors via automated video analysis combined with instrument-based measurements of eating, drinking, food choice, sucrose preference and wheel running. Our custom system is able to record 16 mice simultaneously, each in a modified version of a standard homecage with 24/7 video and device monitoring. We have also designed data intake and processing streams to both handle and graph data on a secure webserver for daily checks and ongoing monitoring before diving into deeper analyses. We have also integrated recording of electrophysiology over weeks with automated analytics pipelines being built.

Results: We have studied two cohorts of mice. The first was a proof of principle cohort where circadian rhythms were studied by inverting the timing of the daily 12:12 hour lighting. In this cohort we found 12 hour shifts of behavioral markers as predicted, validating our system. In a second cohort we gave corticosterone in the drinking water and initial results have indicated changes in sucrose preference and wheel running. We also see remarkable inter-individual variation even at baseline indicating we may have a system that is able to better capture human-like individual variance.

Conclusions: Our Mouse Digital Phenotyping system has been developed and shown to work for deep characterization of circadian rhythms and initial results show that it can also measure effects of a chronic stress model. We look forward to deepening our characterization of circadian rhythms, sleep and stress - and how those link to brain electrophysiologic activity.